Crimson Trace LG-350G Smith & Wesson, J-Frame Round Butt Lasergrip, Green NAN Made in USA ULTRA BRIGHT GREEN LASER: Features a 5mW peak, 515-532nm, Class 3R visible green laser - the brightest beam allowed by law. INSTINCTIVE ACTIVATION: Front activation button engages the laser immediately when the firearm is held in a normal firing grip. This is the feature that sets Crimson Trace apart from the rest. OVER TWO HOURS OF BATTERY LIFE: Powered by four #2016 Batteries (included). This product is eligible for Crimson Traces Free Batteries For Life Program. FITS: Smith & Wesson J-Frame Round Butt Revolvers EASY INSTALLATION: User installed- no gunsmithing required. Factory sighted at 50 feet, but is fully user adjustable for Windage and Elevation with provided tool. This model features a master ON/OFF switch for completely powering down the unit.